O3,ARM: fix some problems with drain/switchout functionality and add Drain DPRINTFs

This patch fixes some problems with the drain/switchout functionality
for the O3 cpu and for the ARM ISA and adds some useful debug print
statements.

This is an incremental fix as there are still a few bugs/mem leaks with the
switchout code. Particularly when switching from an O3CPU to a
TimingSimpleCPU. However, when switching from O3 to O3 cores with the ARM ISA
I haven't encountered any more assertion failures; now the kernel will
typically panic inside of simulation.

1 files changed, 5 insertions, 1 deletions

diff --git a/src/mem/packet_queue.cc b/src/mem/packet_queue.cc
index ab50fd567..77fba8883 100644
--- a/src/mem/packet_queue.cc
+++ b/src/mem/packet_queue.cc
@@ -41,6 +41,7 @@
  *          Andreas Hansson
  */
 
+#include "debug/Drain.hh"
 #include "debug/PacketQueue.hh"
 #include "mem/packet_queue.hh"
 
@@ -168,7 +169,9 @@ PacketQueue::scheduleSend(Tick time)
             em.schedule(&sendEvent, std::max(nextReady, curTick() + 1));
     } else {
         // no more to send, so if we're draining, we may be done
-        if (drainEvent && !sendEvent.scheduled()) {
+        if (drainEvent && transmitList.empty() && !sendEvent.scheduled()) {
+            DPRINTF(Drain, "PacketQueue done draining,"
+                    "processing drain event\n");
             drainEvent->process();
             drainEvent = NULL;
         }
@@ -201,6 +204,7 @@ PacketQueue::drain(Event *de)
 {
     if (transmitList.empty() && !sendEvent.scheduled())
         return 0;
+    DPRINTF(Drain, "PacketQueue not drained\n");
     drainEvent = de;
     return 1;
 }